Kongs are widely used for therapy and prevention of boredom, separation anxiety and other behavioral issues. The strong, thick, flexible walls satisfy a dogs natural need to chew while it cleans teeth and conditions gums. They are unmatched for resilience, durability, bounce and the Ultra-FlexÅ rubber is nontoxic, nonabrasive, non-splintering and does not get sharp when chewed. Kong toys are enthusiastically used and recommended by veterinarians, trainers, dog professionals and satisfied customers world wide.